Re: Air Canada DC-9s questions

From:         speedpuppy <dargonis@nando.net>
Organization: Nando.net Public Access
Date:         11 Oct 96 19:44:48 
References:   1
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Jean-Francois Mezei wrote:
> On a recent DC-9 flight on Air Canada (LGA-YUL), I noticed the year
> "1967" on a plaque on the left side of the entry door frame. (My first
> flight in a DC-9 in years)
>
> I would be interested in knowing when the DC-9s were first introduced,
> and when they were at their apex of sales, and when did sales of new
> DC-9s stop ? Was the DC-9 immediatly replaced by the MD80 or was there a
> few years in between ?

you got me there about the sales...i believe the first revenue flight of
the dc9  a -10 series was in 1962...the md80 entered into service in
1980..while a stretch version of the dc9 -50 series it was a decendant
not a replacement of the orginal dc9...you most likely flew on a -30
series  longer than the -10...( which did not have any slats (leading
edge devices)). the next jump was the -30  holds about 100 people give
or take depending upon airline configuration...then came the -50 series
made popular at eastern air lines  held about 120 or so...then the -80
or md80 holds about 144  next version is the md90 smaller than the 80
but more powerful and fuel efficient.

> Are there still a lot or DC9s that were built prior to 1970 in service
> in North America, or was the one I flew a true/rare "vintage" one ?

USAIR operates some 79 dc-9 30 series most are in the late 60- early 70s
age...but this is not old or young for a modern well kept jetliner..
lifespan usually is dictated by cycles ( takeoffs and landings 1up/down
= 1 cycle ususally around 100000 cycles causes most of the pressure bulk
heads to exceed tolerance then while it is replaceable it might not be
cost effective thus this becomes the life limit  however you can replace
parts with new ones and thus the "age" of the jet might not reflect the
orginal production date

> Also, I noticed a hole in the leading edge of the tail, just above the
> fuselage. Is this an air intake for the apu ?

You were close the round hole aircraft right ( always reference as if
you were in cockpit seated forward facing) is the apu exhaust....

aircraft left has a round hole with a butterfly valve in it this is for
pressurization control...

> Also, the rubber gasket on the front door seemed quite different from
> other more modern planes. Is this the actual air tight barrier when door
> is closed, of does this very visible rubber gasket serve a protective or
> other function ?

it also prevents rain from entering while deressurized with door closed
( on ground).. the door is a plug type door and cannot be opened in
flight with aircraft pressurized...you must bring the door out about 1/2
inch then pivot inside airpland about 10inches then push it out...also
in flight the rubber seal ( one smaller and hidden behind the large one
you saw is the actual door seal...)

> Finally, through an opening between the wall and overhead bins, I
> noticed a copper pipe (looked like copper) running along the wall with
> some hookups for every row. The pipe was about 1cm in diameter. Had it
> not been for the Valuejet crash where those oxygen generators were
> described, I would have thought that this pipe would have been the
> oxygen supply. I seems too small for the air supply for the over head
> air nozzles. What would this pipe be used for ? Is it possible that on
> some models of DC9s, the oxygen was centrally supplied through such a
> pipe as opposed to having individual generators over every row ?

with out seeing the exact tube i cannot verify this but you are correct
prior to o2 gens..there was a big o2 bottle in the cockpit that would
supply the cabin...actually the generators are smaller and safer (
guarentee flow at each station) than the old way...also saves weight...


hope this helped

Dave Argonis
dc9 md80 bac 111 b 737-300 sa-227